Postmark

Postmark is a hosted email delivery service focused on transactional mail. It is named as an email driver in the MainSDK requirements, so email.send() and email.marketing() could deliver through it. Pick it if your team already sends through Postmark.

email:
  driver: postmark

mail:
  driver: postmark

Before you start

1. Create a Postmark server for this app and copy its server API token.
2. Add your sending domain and the DNS records Postmark gives you (DKIM and a return-path record).
3. Postmark separates transactional and broadcast mail into message streams; marketing email belongs on a broadcast stream.

Store the token in your secrets manager.

Configure

email:
  driver: postmark                 # planned driver, not in the spec yet
  key: secret:POSTMARK_SERVER_TOKEN   # suggested name

A literal key fails to load with MAIN-CONFIG-0004.

Use it

import { email } from "mainsdk";

await email.send({ to: user.email, template: "receipt", data: { orderId: order.id } });

Local development and testing

mainsdk dev sends every email to the local inbox. createTestApp() from @mainsdk/testing runs email on its in-memory fake, and chaos.on("email", { outage: true }) simulates an outage.

What MainSDK adds on top

• Marketing email does not compile without an unsubscribe.
• Unsubscribes, bounces and complaints suppressed for every later send.
• No tracking pixels or rewritten links by default; a retry never sends twice.

See Email.

Limits and notes

• Planned driver, not in the spec yet. The email-notify spec ships Resend, Amazon SES and the local inbox; Postmark comes through the driver kit later.
• How marketing sends map to a Postmark message stream is not decided yet.

Swap to or from it

email:
  driver: resend   # was postmark

Email is stateless, so the swap needs no migration; verify your domain with the new provider first.

FAQ

Can I use Postmark today? Not through MainSDK yet. Use Resend or Amazon SES.

Next

• Email
• Resend, Amazon SES and SMTP

Open questions